Ramona Quimby, Age 8 is the sixth book in the Ramona Quimby series, focusing on Ramona adjusting to her third grade year, in a new school.
The story opens on the Quimby sisters preparing to start a new school year-- Ramona Quimby is starting third grade at a different elementary school than her previous one, while Beezus Quimby is starting junior high. On the way there, they run into the Kemp siblings, and Willa Jean Kemp is starting preschool, though she claims she's going to "kidnergarten", thinking that's where the kids are.
When Ramona gets to the school, she meets a boy named Danny, who calls her "Bigfoot" due to her large, new shoes and steals her eraser, playing catch with it with some other boys. Ramona calls the boys "yucky yard apes", earning Danny the nickname "Yard Ape". The next day, the teacher introduces the class to Sustained Silent Reading, or Drop Everything and Read (D.E.A.R), and after school, Willa Jean ropes Ramona and Howie Kemp into a roleplay of "Froggie Went a'Courting" with Howie in the role of Froggie, herself as Miss Mouse, and Ramona as Uncle Rat.
Some time later, hard-boiled eggs become a fad at school, and Ramona begins eating them at lunch despite disliking them. She brings an egg to school, then goes to science class, where they study fruit fly larvae that live in blue-dyed oatmeal. At lunch, she tries cracking her egg on her head, but it turns out that Dorothy Quimby accidentally put a raw egg in Ramona's lunch box instead of the boiled one, so Ramona gets egg in her hair, prompting Yard Ape to call her "Egghead". The school secretary washes it out, but Ramona fears that Mrs. Whaley has a low opinion of her, since she overheard her saying, "What a nuisance" on the phone and calling her a show-off.
That evening, the Quimbys bicker over dinner when the girls refuse to eat their food upon realising their parents served them tongue. As punishment, the parents make the girls cook dinner on Sunday night. The girls try to be especially good all Sunday, but the parents make them cook dinner anyway, and they end up making a decent cornbread, though Ramona isn't sure if her parents like it or are pretending to like it.
One day, Ramona feels a bit out-of-sorts in the morning and eventually throws up in class, making her fear of being a nuisance even worse. She turns out to have stomach flu and spends a few days off school, but when she gets back, she is able to do a book report for a story about a cat.
On a rainy afternoon, Beezus is grumpy about not being allowed to go to a slumber party, but cheers up when the family goes to a burger joint.